/*
* YUI Compressor
* http://developer.yahoo.com/yui/compressor/
* Author: Julien Lecomte - http://www.julienlecomte.net/
* Copyright (c) 2011 Yahoo! Inc. All rights reserved.
* The copyrights embodied in the content of this file are licensed
* by Yahoo! Inc. under the BSD (revised) open source license.
*/
package com.yahoo.platform.yui.compressor;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.Hashtable;
class ScriptOrFnScope {
private int braceNesting;
private ScriptOrFnScope parentScope;
private ArrayList subScopes;
private Hashtable identifiers = new Hashtable();
private Hashtable hints = new Hashtable();
private boolean markedForMunging = true;
private int varcount = 0;
ScriptOrFnScope(int braceNesting, ScriptOrFnScope parentScope) {
this.braceNesting = braceNesting;
this.parentScope = parentScope;
this.subScopes = new ArrayList();
if (parentScope != null) {
parentScope.subScopes.add(this);
}
}
int getBraceNesting() {
return braceNesting;
}
ScriptOrFnScope getParentScope() {
return parentScope;
}
JavaScriptIdentifier declareIdentifier(String symbol) {
JavaScriptIdentifier identifier = (JavaScriptIdentifier) identifiers.get(symbol);
if (identifier == null) {
identifier = new JavaScriptIdentifier(symbol, this);
identifiers.put(symbol, identifier);
}
return identifier;
}
JavaScriptIdentifier getIdentifier(String symbol) {
return (JavaScriptIdentifier) identifiers.get(symbol);
}
void addHint(String variableName, String variableType) {
hints.put(variableName, variableType);
}
void preventMunging() {
if (parentScope != null) {
// The symbols in the global scope don't get munged,
// but the sub-scopes it contains do get munged.
markedForMunging = false;
}
}
private ArrayList getUsedSymbols() {
ArrayList result = new ArrayList();
Enumeration elements = identifiers.elements();
while (elements.hasMoreElements()) {
JavaScriptIdentifier identifier = (JavaScriptIdentifier) elements.nextElement();
String mungedValue = identifier.getMungedValue();
if (mungedValue == null) {
mungedValue = identifier.getValue();
}
result.add(mungedValue);
}
return result;
}
private ArrayList getAllUsedSymbols() {
ArrayList result = new ArrayList();
ScriptOrFnScope scope = this;
while (scope != null) {
result.addAll(scope.getUsedSymbols());
scope = scope.parentScope;
}
return result;
}
int incrementVarCount() {
varcount++;
return varcount;
}
void munge() {
if (!markedForMunging) {
// Stop right here if this scope was flagged as unsafe for munging.
return;
}
int pickFromSet = 1;
// Do not munge symbols in the global scope!
if (parentScope != null) {
ArrayList freeSymbols = new ArrayList();
freeSymbols.addAll(JavaScriptCompressor.ones);
freeSymbols.removeAll(getAllUsedSymbols());
if (freeSymbols.size() == 0) {
pickFromSet = 2;
freeSymbols.addAll(JavaScriptCompressor.twos);
freeSymbols.removeAll(getAllUsedSymbols());
}
if (freeSymbols.size() == 0) {
pickFromSet = 3;
freeSymbols.addAll(JavaScriptCompressor.threes);
freeSymbols.removeAll(getAllUsedSymbols());
}
if (freeSymbols.size() == 0) {
throw new IllegalStateException("The YUI Compressor ran out of symbols. Aborting...");
}
Enumeration elements = identifiers.elements();
while (elements.hasMoreElements()) {
if (freeSymbols.size() == 0) {
pickFromSet++;
if (pickFromSet == 2) {
freeSymbols.addAll(JavaScriptCompressor.twos);
} else if (pickFromSet == 3) {
freeSymbols.addAll(JavaScriptCompressor.threes);
} else {
throw new IllegalStateException("The YUI Compressor ran out of symbols. Aborting...");
}
// It is essential to remove the symbols already used in
// the containing scopes, or some of the variables declared
// in the containing scopes will be redeclared, which can
// lead to errors.
freeSymbols.removeAll(getAllUsedSymbols());
}
String mungedValue;
JavaScriptIdentifier identifier = (JavaScriptIdentifier) elements.nextElement();
if (identifier.isMarkedForMunging()) {
mungedValue = (String) freeSymbols.remove(0);
} else {
mungedValue = identifier.getValue();
}
identifier.setMungedValue(mungedValue);
}
}
for (int i = 0; i < subScopes.size(); i++) {
ScriptOrFnScope scope = (ScriptOrFnScope) subScopes.get(i);
scope.munge();
}
}
}